Pulled carb, found this

[Steve079]

I decided to run the motor, down at the local lake, engine fired up second pull. Would not idle, and had a steady miss at lower RPM's. So I removed the carb, and...

This is what I found.

This white stuff is inside the reed housing, or cage, and is keeping the reed valve from seating in the one shown at the rear of the motor. The front reed cage is clean.

The throttle butterfly(?) was frozen with buildup, and was stuck tight. I removed the 2 small screws, but it seems that the butterfly is too large? It doesn't want to fit in, and lay flat across that rod that runs through the the body.

It appears in the area where the butterfly sits, that the metal is erroded and pitted a bit, but could it just be build up?
Is this engine worth continuing with?

Thank you.

 

[Joe Reeves]

Re: Pulled carb, found this

It appears that the engine has either been underwater OR has had water enter it via some other process. Removing those two small screws from the throttle butterfly wasn't a good idea. The butterfly fits as it should BUT the critical positioning of it in order to reinstall those two small screws can be time consuming. That butterfly DOES NOT ever sit perfectly vertical... the idle position has it setting in the carburetor throat at what might be a 10 degree or so angle.

Worth continuing with?? You will need to be the judge of that decision. Check both cylinders for compression before going further.

 

[1946Zephyr]

Re: Pulled carb, found this

Holy cow. That doesn't look good. Like Joe Reeves said, those butterfly screws should never bee taken out. The threads are mashed on the end, so they don't vibrate out, should they happen to loosen up. If you do happen to get the butter fly mounted back in there correctly, you'll want to use licktite on those screws, so they don't vibrate out.

But yea, before going any further, I would check things over really good, to see if it's worth dealing with. With that much corrosion on the inside of the manifold, there is no telling how much is inside the crankcase. Do a compression test.

 

[Steve079]

Re: Pulled carb, found this

Can I do a compression check without warming up the motor? The carb is off, as shown. How would you go about removing that buildup without it winding up in the cylinders?

 

[Solittle]

Re: Pulled carb, found this

You can do a compression check on a cold engine. What do the plugs look like? Do that before you mess with the other stuff.

 

[Steve079]

Re: Pulled carb, found this

Prior to running it at the lake, I had installed a new impeller, oil in L/U, gas lines and new spark plugs. I ran the motor for 10-15 minutes; it wasn't going to idle, had a steady miss at the lower rpm as it was running, so back on the trailer it went. I pulled the bottom plug, it had some blackish deposits on it. the old plugs were J4J's, since I was told they were no longer made, I guess they had been in there a while, but aside from heavy deposits, didn't look too abnormal. I'll check the compression in the morning, and let you know.

thank you all for the help

 

[dkonrai]

Re: Pulled carb, found this

steve,
glad you made it here! told you there was some great guys here!!!
dino

 

[Haffiman]

Re: Pulled carb, found this

You already had it running in the state as shown - clean up as best you can and put it back in the water and test. If possible try to source out a 'new' leaf plate from a junk motor/yard and replace. You can not run a compression test without leaf-plate and valves installed.

 

[1946Zephyr]

Re: Pulled carb, found this

By the way, what kind of motor are we working on here?

Reguardless of the motor, I would put J6C's back in it. It sounds like you have an older OMC, if it had J4J's in it.

 

[JB]

Re: Pulled carb, found this

You can not run a compression test without leaf-plate and valves installed.

I don't agree with that. Neither is involved in testing compression.

Do agree with Zephyr; it would be very helpful to have a model number or at least some description of the outboard.

 

[Haffiman]

Re: Pulled carb, found this

I don't agree with that. Neither is involved in testing compression.

Do agree with Zephyr; it would be very helpful to have a model number or at least some description of the outboard.

When piston goes down, it will be no crank-case compression pushing the 'fuel/air' mix up the by-pass ports to the top of the piston. That is among others why you have leaf valves.They create a suction to get fuel/air in (piston goes up) - they create a pressure to bring it to the top of the piston (piston goes down). You may get a reading of what gets compressed from top of port and up, but will be far less than with the read valves in place.

 

[Steve079]

Re: Pulled carb, found this

Thanks again for the help, the engine is a '65 9.5. Evinrude 9522

 

[tx1961whaler]

Re: Pulled carb, found this

When piston goes down, it will be no crank-case compression pushing the 'fuel/air' mix up the by-pass ports to the top of the piston. That is among others why you have leaf valves.They create a suction to get fuel/air in (piston goes up) - they create a pressure to bring it to the top of the piston (piston goes down). You may get a reading of what gets compressed from top of port and up, but will be far less than with the read valves in place.

What is the normal crankcase pressure, like 3 psi?

 

[Steve079]

Re: Pulled carb, found this

What reading should I expect to see, with a cold motor, pull starter, no carbs? From what I've read, around 60?

 

[kbait]

Re: Pulled carb, found this

60 would be adequate. Hard to spin over quickly w/spool-type recoils. You need to somehow clean up those gunked reed valves so they seal before it'll get fuel to that cylinder.

 

[Haffiman]

Re: Pulled carb, found this

What is the normal crankcase pressure, like 3 psi?

It is no spec as it will vary from negative, piston going up to positive - piston going down. As we are dealing with a 'gas' that may be compressed, it will be a rather difficult calculation where even the rpm will come in play. The lower the rpm, the lower compression and vacuum.

 

[dkonrai]

Re: Pulled carb, found this

steveo,
you could always use a drill to spin the motor. just make sure u put a few drops of oil in the cylinders so they dont get scored.
dino

 

[JB]

Re: Pulled carb, found this

When piston goes down, it will be no crank-case compression pushing the 'fuel/air' mix up the by-pass ports to the top of the piston. That is among others why you have leaf valves.They create a suction to get fuel/air in (piston goes up) - they create a pressure to bring it to the top of the piston (piston goes down). You may get a reading of what gets compressed from top of port and up, but will be far less than with the read valves in place.

At cranking speed there is no scavenging required, inside of the cylinder reaches ambient pressure through the exhaust ports. That is why the throttle position means nothing in compression testing. This fact has been tested and proven thousands of times.

Your 2 stroke running theory is right on, but it just doesn't work at compression testing speeds.

 

[Steve079]

Re: Pulled carb, found this

Dino,

you could always use a drill to spin the motor.

Huh? I guess I need to go look at the motor. Are you talking about spinning it from the nut on top of the flywheel? I have an 1/2 air impact ( tire changes) and a hefty compressor. that ought to spin it.

 

[1946Zephyr]

Re: Pulled carb, found this

At cranking speed there is no scavenging required, inside of the cylinder reaches ambient pressure through the exhaust ports. That is why the throttle position means nothing in compression testing. This fact has been tested and proven thousands of times.

Your 2 stroke running theory is right on, but it just doesn't work at compression testing speeds.

Yea, I have tested an older 10hp with a bypass cover missing and got 80psi on each hole. I was told that you just needed a head present to do a compression test.

I second what kbait says. Your reed vales need to be clean and rust free to operate correctly, because they work to get fuel mix to the cylinder.